Verified answer

"One of us has a compass" is the correct one.

Second one is correct. The first is awkward.

You could say "I have a compass', 'she has a compass', 'we have a compass' etc.

One of us has a compass, I believe

One of us has a compass.

"One of us has a compass."

A verb agrees in number with the subject, which is not necessarily the noun closest to it. In this case, the subject is "one," and "of us" is a prepositional phrase. (Besides, "us" is in the wrong case to be a subject!)

One of us has.... is the correct way